refactor: replace expand-tilde package by modernized local reimplementation

package.json

@@ -12,10 +12,8 @@
     "@actions/core": "^3.0.1",
     "@actions/exec": "^3.0.0",
     "@actions/glob": "^0.7.0",
-    "@types/expand-tilde": "^2.0.2",
     "@types/node": "^26.6.5",
     "@types/semver": "^7.8.0",
-    "expand-tilde": "^2.0.2",
     "get-pnpm": "^0.0.8",
     "semver": "^7.8.5",
     "yaml": "^2.9.1"

src/inputs/index.ts

@@ -1,8 +1,8 @@
 import { existsSync } from 'node:fs'
+import os from 'node:os'
 import path from 'node:path'
 
 import { getBooleanInput, getInput, InputOptions } from '@actions/core'
-import expandTilde from 'expand-tilde'
 
 import { resolveRegistry } from '../install-pnpm/registry.js'
 
@@ -61,6 +61,26 @@ function parseRuntime (): RuntimeInput | undefined {
 
 const MANIFEST_NAMES = ['package.json', 'package.yaml'] as const
 
+/**
+ * Expands a leading tilde in a file path.
+ *
+ * @param inputPath The file path to expand.
+ * @returns The expanded path.
+ */
+function expandTilde (inputPath: string): string {
+  const home = os.homedir()
+
+  if (inputPath.startsWith('~+')) {
+    return path.join(process.cwd(), inputPath.slice(2))
+  }
+
+  if (inputPath.startsWith('~')) {
+    return home ? path.join(home, inputPath.slice(1)) : inputPath
+  }
+
+  return inputPath
+}
+
 /**
  * `working-directory` says where the project is; `package-json-file` said
  * which file to read. The second is deprecated onto the first, because the